The proposed work involved three interrelated tasks: The study of the levels and effects of salicylate challenge tests on markers of free radical processes in a population of about 500 individuals with neurodegenerative disorders and controls. The development of robust methods for these compounds for the research and clinical market using new technologies for chromatographic separation and electrochemical detection. The development of point-of-need technologies for assessing specific (glutathione) and general indicators of oxidative protection. The principle new methodological developmental efforts focus on nitrated amino acids, DNA adducts, and benzoates. About 60 other indicators of metabolic status (purines, tyrosine, tryptophan metabolites, and antioxidant vitamins) will be monitored as test co-variables. The goals are to establish the utility of free radical challenge test and markers in clinical assessment, and to provide laboratory and point-of- need assay technology to utilize then effectively. PROPOSED COMMERCIAL APPLICATION: The work is expected to result in novel tests and LC hardware for clinical laboratory monitoring of oxidative stress markers and in point-of-need disposable monitors for glutathione and oxidative stress.